With the advent of ventilated brake discs, the “shop closed” - the destruction of this guarantees an accident! That's why when disks grind to a thickness of less than 17.8 mm, good people change them for new ones. But at the same time, incidents are possible.
In the photo 1 - a disc of one reputable company was bought (taking into account the recommendations of the sellers of a large Moscow store!) For VAZ 2110 3. We will pay tribute to the manufacturer: there is no VAZ in the list of brands for which this disc is suitable. And the buyer believed the seller.
We put these discs without any problems - the thickness of the landing part, the diameter of the holes for the bolts, etc. - everything went perfectly. Go! While the driver braked smoothly, the car behaved normally. But he pressed harder - the front end shook! Then they removed the discs and measured the diameter of the central hole, with which the disc sits on the hub. It turned out that it is 0.5 mm larger than that of the VAZ! When the pads “pinched” the disk with full force, it will shift within the limits of its “freedom” - both radial and axial runout will appear, and the imbalance too - the disk is massive!
The owner had to buy VAZ wheels. They stopped shaking with them - they are centered on the hubs quite accurately.
In photo 2 - a device made from a discarded old drum (all front-wheel drive VAZs are identical for now). Clever already understood and appreciated everything! Having put on this thing instead of the native drum, ask the assistant to step on the pedal - and you will immediately see how the pistons work in the cylinder, if they stick and so on. Sometimes this eliminates painful guesses!